1. Technical Field
The present invention pertains to lenses for radio frequency transmissions. In particular, the present invention pertains to a radio frequency (RF) lens that includes a photonic crystal structure and suppresses side-lobe features.
2. Discussion of Related Art
Radio frequency (RF) transmission systems generally employ dish antennas that reflect RF signals to transmit an outgoing collimated beam. However, these types of antennas tend to transmit a substantial amount of energy within side-lobes. Side-lobes are the portion of an RF beam that are dictated by diffraction as being necessary to propagate the beam from the aperture of the antenna. Typically, suppression of the side-lobe energy is problematic for RF systems that are required to be tolerant of jamming, and is critical for reducing the probability that the transmitted beam is detected (e.g., an RF beam is less likely to be detected, jammed or eavesdropped in response to suppression of the side-lobe energy).